Implemented: FS#1113 - Force client to use only allowed IPs

1) Edit a domain: The selected domain is also selected in the dropdown-list
2) Edit a domain: The admin can now select any domain not only his/her

Fixed a bug: if the domain-module is used and there are NO domains in the list, then the user was able to free edit the domain-name. This bug is fixed now and a empty list is generated, so the user can enter only a empty name!

Added a new module called "domain". With this module you can manage all domains (web + mail). Per default this module is not active. To activate it, you have to change the System Interface Config -> domains -> use the domain module. You also have to activate the domain-module for the admin (and for every client if you want). Important: you can not use this module if you have reseller!

Fixed: FS#1118 - [client_id] is not resolved in .php-fcgi-starter

Additionally fixed a bug in web quota calculation.

Added a global default for the .htaccess allow_override setting.

Improved client and reseller limit checks

Fixed: FS#787 - A sub-client can see all the clients on the system in the client drop down list